You can update your credit card information for your subscription from your dashboard! but only if your payment method is Paddle.
First, click on the subscription you would like to update. Then, click on the three dots icon and "Update Payment Card" option, as you see in the screenshot below:
Your browser will open a new tab where you can update the payment details with Paddle, the payment processor. It will look like this:
Once you have entered your new card information, click the "Update payment method" button to save your payment information.